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How Do You Know If The Catalytic Converter Is Bad?

2.1K views 3 replies 4 participants last post by  NorcalBrick  
#1 ·
Does anyone know how to test the catalytic converter to determine if it is bad? ('83 Volvo 245DL)

Any help is much appreciated
 
#2 ·
You would have to take it to an exaust shop to be certain but there are a couple of indicators.

You will smell a strong sulfer odor (Rotten egg) smell when the engine is at normal operating temp.

The engine will lack power and be VERY sluggish when accelerating.

I would take it to a muffler shop and have them check it, They are a little pricey but why replace it if you dont have to.
 
#3 · (Edited by Moderator)
The exhaust shop that I use just pokes a hole and checks for flow. They really shouldn't charge you to test it. If they do want to charge you then another shop might be better. Also check the flow behind the tailpipe. It should be strong. But yeah, you will have no power.

You can buy replacement cats for around $80 online. Installation is what will cost you.
 
#4 ·
A bit late getting in on this one, but I had trouble getting my 240 to pass smog here in CA, the major reason being the cat was bad. The garage I usually use told me an easy way to check for proper function is to use an infrared thermometer to take temp readings of the exhaust pipe just before entering and just after leaving the cat. Because of the chemical reaction taking place in a properly working converter, the downstream temp should be significantly higher than the upstream temp. When I checked mine it was almost identical on both sides of the cat. This is a "quick and dirty" test, so it isn't 100% accurate in all scenarios, but if your cat is completely shot this will show it.